Field effect transistors (FETs) introduced with mechanical stress applied to channel regions have enhanced driving strength due to increased carrier mobility in the channel regions. In some approaches, in an FET, source and drain regions on opposite sides of a gate include stressor regions embedded in a body structure. Lattice mismatch between the material of a channel region and the material of the embedded stressor regions causes mechanical stress applied to the channel region. The magnitude of the mechanical stress is dependent on the proximity of the embedded stressor regions to the channel region, and the volumes of the embedded stressor regions. However, when forming recesses in the body of the FET in which the stressor material is to be grown, the profiles of the recesses is dependent on a loading effect of neighboring geometry which can vary from a FET to FET, thereby resulting in non-uniformity of device performance.
Like reference symbols in the various drawings indicate like elements.